The initial study of [123I] INER will be completed in two parts. Once Part A (Preliminary whole body biodistribution) is completed, Part B (Serial dynamic SPECT assessment of regional brain uptake and washout and plasma metabolite analysis to determine the brain penetrance and regional distribution and washout counts following 123-I INER injection) will commence. All study procedures will be conducted at the Institute for Neurodegenerative Disorders (IND) and Molecular NeuroImaging (MNI) in New Haven, CT. All subjects will undergo written informed consent and a screening evaluation including baseline clinical laboratory testing, and a baseline physical and neurological evaluation.